Adding URL handling

src/components/App/__snapshots__/test.js.snap

@@ -5,7 +5,6 @@ exports[`App rendering 1`] = `
   <Translate(Form)
     downloadUrls={Array []}
     onSubmit={[Function]}
-    permalinkUrl="#permalink"
     syntaxes={
       Object {
         "js": "JavaScript",

src/components/App/index.js

@@ -1,6 +1,7 @@
 import React from 'react';
 import PropTypes from 'prop-types';
 import { translate } from 'react-i18next';
+import URLSearchParams from 'url-search-params';
 
 import style from './style.css';
 
@@ -14,6 +15,15 @@ class App extends React.PureComponent {
     syntaxes
   }
 
+  componentDidMount() {
+    window.addEventListener('hashchange', this.handleHashChange);
+    this.handleHashChange();
+  }
+
+  componentWillUnmount() {
+    window.removeEventListener('hashchange', this.handleHashChange);
+  }
+
   setSvgUrl(element) {
     try {
       const type = 'image/svg+xml';
@@ -68,9 +78,40 @@ class App extends React.PureComponent {
   }
 
   handleSubmit = ({expr, syntax}) => {
+    if (expr) {
+      const params = new URLSearchParams({ syntax, expr });
+      document.location.hash = params.toString();
+    }
+  }
+
+  handleHashChange = () => {
+    const query = document.location.hash.slice(1);
+    const params = new URLSearchParams(query);
+    const { expr, syntax } = (() => {
+      if (params.get('syntax')) {
+        return {
+          syntax: params.get('syntax'),
+          expr: params.get('expr')
+        };
+      } else {
+        // Assuming old-style URL
+        return {
+          syntax: 'js',
+          expr: query
+        };
+      }
+    })();
+
+    if (!expr) {
+      return;
+    }
+
     console.log(syntax, expr); // eslint-disable-line no-console
     this.setState({
-      image: demoImage
+      image: demoImage,
+      permalinkUrl: document.location.toString(),
+      syntax,
+      expr
     }, async () => {
       await this.image.doReflow();
       this.setSvgUrl(this.image.svg);
@@ -81,7 +122,7 @@ class App extends React.PureComponent {
   imageRef = image => this.image = image
 
   render() {
-    const { svgUrl, pngUrl, syntaxes, image } = this.state;
+    const { svgUrl, pngUrl, permalinkUrl, syntax, expr, syntaxes, image } = this.state;
     const downloadUrls = [
       svgUrl,
       pngUrl
@@ -91,7 +132,9 @@ class App extends React.PureComponent {
       <Form
         syntaxes={ syntaxes }
         downloadUrls={ downloadUrls }
-        permalinkUrl="#permalink"
+        permalinkUrl={ permalinkUrl }
+        syntax={ syntax }
+        expr={ expr }
         onSubmit={ this.handleSubmit }/>
       <Message type="error" heading="Sample Error">
         <p>Sample error message</p>

src/components/Form/__snapshots__/test.js.snap

@@ -9,6 +9,8 @@ exports[`Form rendering 1`] = `
   >
     <textarea
       autoFocus={true}
+      name="expr"
+      onChange={[Function]}
       onKeyPress={[Function]}
       placeholder="translate(Enter regular expression to display)"
     />
@@ -22,7 +24,11 @@ exports[`Form rendering 1`] = `
     <div
       className="select"
     >
-      <select>
+      <select
+        name="syntax"
+        onChange={[Function]}
+        value="js"
+      >
         <option
           key="js"
           value="js"
@@ -54,6 +60,8 @@ exports[`Form rendering with download URLs 1`] = `
   >
     <textarea
       autoFocus={true}
+      name="expr"
+      onChange={[Function]}
       onKeyPress={[Function]}
       placeholder="translate(Enter regular expression to display)"
     />
@@ -67,7 +75,11 @@ exports[`Form rendering with download URLs 1`] = `
     <div
       className="select"
     >
-      <select>
+      <select
+        name="syntax"
+        onChange={[Function]}
+        value="js"
+      >
         <option
           key="js"
           value="js"
@@ -124,6 +136,8 @@ exports[`Form rendering with permalink URL 1`] = `
   >
     <textarea
       autoFocus={true}
+      name="expr"
+      onChange={[Function]}
       onKeyPress={[Function]}
       placeholder="translate(Enter regular expression to display)"
     />
@@ -137,7 +151,11 @@ exports[`Form rendering with permalink URL 1`] = `
     <div
       className="select"
     >
-      <select>
+      <select
+        name="syntax"
+        onChange={[Function]}
+        value="js"
+      >
         <option
           key="js"
           value="js"

src/components/Form/index.js

@@ -8,12 +8,34 @@ import ExpandIcon from 'feather-icons/dist/icons/chevrons-down.svg';
 
 import style from './style.css';
 
-class Form extends React.Component {
+class Form extends React.PureComponent {
+  constructor(props) {
+    super(props);
+    this.state = {
+      syntax: props.syntax || Object.keys(props.syntaxes)[0],
+      expr: props.expr
+    };
+  }
+
+  componentWillReceiveProps(next) {
+    if (this.props.expr !== next.expr) {
+      this.setState({
+        expr: next.expr
+      });
+    }
+
+    if (this.props.syntax !== next.syntax) {
+      this.setState({
+        syntax: next.syntax
+      });
+    }
+  }
+
   handleSubmit = event => {
     event.preventDefault();
     this.props.onSubmit.call(this, {
-      expr: this.textarea.value,
-      syntax: this.syntax.value
+      expr: this.state.expr,
+      syntax: this.state.syntax
     });
   }
 
@@ -23,9 +45,7 @@ class Form extends React.Component {
     }
   }
 
-  textareaRef = textarea => this.textarea = textarea
-
-  syntaxRef = syntax => this.syntax = syntax
+  handleChange = event => this.setState({ [event.target.name]: event.target.value })
 
   permalinkAction() {
     const { permalinkUrl } = this.props;
@@ -55,17 +75,23 @@ class Form extends React.Component {
 
   render() {
     const { syntaxes, t } = this.props;
+    const { expr, syntax } = this.state;
 
     return <div className={ style.form }>
       <form onSubmit={ this.handleSubmit }>
         <textarea
-          ref={ this.textareaRef }
+          name="expr"
+          value={ expr }
           onKeyPress={ this.handleKeyPress }
+          onChange={ this.handleChange }
           autoFocus
           placeholder={ t('Enter regular expression to display') }></textarea>
         <button type="submit"><Trans>Display</Trans></button>
         <div className={ style.select }>
-          <select ref={ this.syntaxRef }>
+          <select
+            name="syntax"
+            value={ syntax }
+            onChange={ this.handleChange }>
             { Object.keys(syntaxes).map(id => (
               <option value={ id } key={ id }>{ syntaxes[id] }</option>
             )) }
@@ -83,6 +109,8 @@ class Form extends React.Component {
 }
 
 Form.propTypes = {
+  expr: PropTypes.string,
+  syntax: PropTypes.string,
   syntaxes: PropTypes.object,
   onSubmit: PropTypes.func,
   permalinkUrl: PropTypes.string,

src/components/Form/test.js

@@ -50,13 +50,13 @@ describe('Form', () => {
       const onSubmit = jest.fn();
       const component = build({ onSubmit });
       const eventObj = { preventDefault: jest.fn() };
-      component.find(Form).instance().textarea.value = 'Test textarea value';
+      component.find(Form).instance().setState({ syntax: 'test', expr: 'Test expression' });
       component.find('form').simulate('submit', eventObj);
 
       expect(eventObj.preventDefault).toHaveBeenCalled();
       expect(onSubmit).toHaveBeenCalledWith({
-        expr: 'Test textarea value',
-        syntax: 'js'
+        expr: 'Test expression',
+        syntax: 'test'
       });
     });